[AVR] ATmega8 Zerocross Detection circuit

/*
 *  Written in AVR Studio 5 / AVR Studio 6
 *  Compiler: AVR GNU C Compiler (GCC)
 *
 *  Author: AVR Tutorials
 *  Website: www.AVR-Tutorials.com
*/
 
#include <avr/io.h>
#include <avr/interrupt.h>
 
#define F_CPU 16000000UL
#include <util/delay.h>
 
#define DataPort	PORTC	// Using PortC as our Dataport
#define DataDDR		DDRC

//Interrupt Service Routine for INT0
ISR(INT0_vect)
{
	unsigned char i, temp;
	cli();
	//_delay_ms(500); // Software debouncing control
 
	//temp = DataPort;	// Save current value on DataPort
 
	/* This for loop blink LEDs on Dataport 5 times*/
	DataPort = 0x00;
	for(i = 0; i<100; i++)
	{
		
		_delay_us(200);	// Wait 5 seconds
	
		//_delay_us(200);	// Wait 5 seconds
	}
 	DataPort = 0xFF;
	//DataPort = temp;	//Restore old value to DataPort	
	sei();
}	
 
int main(void)
{
	DDRD = 1<<PD2;		// Set PD2 as input (Using for interupt INT0)
	PORTD = 1<<PD2;		// Enable PD2 pull-up resistor
 
	DataDDR = 0xFF;		// Configure Dataport as output
	DataPort = 0xFF;	// Initialise Dataport to 1
	
	GICR = 1<<INT0;					// Enable INT0
	MCUCR = 1<<ISC01 | 1<<ISC00;	// Trigger INT0 on rising edge
 
	sei();				//Enable Global Interrupt 
    while(1)
    {
	/*	if(DataPort >= 0x80)
			DataPort = 1;
		else
			DataPort = DataPort << 1;	// Shift to the left
 
		_delay_ms(500);	// Wait 5 seconds */
		if(!(PIN_1 & (1<<SW_1))) //If switch is pressed
		{
			toggle(LED_PORT,LED_1);
			_delay_ms(1000);
		}
		else if(!(PIN_1 & (1<<SW_2))) //If switch is pressed
		{
		toggle(LED_PORT,LED_2);
		_delay_ms(1000);
		}
    }
}